“Our birds instinctively learn to fly on the wake created by the wingtip,” says Duff. “They just figure it out.”

The birds compete for the best position off the wingtip; the others settle into a diagonal line, “surfing” the less intense vortex off each bird.

The pilots fly in the early morning, when the vortices off the wingtips are smooth. As the air heats up and thermal activity rises, it becomes more difficult for the birds to follow, and they move away from the ultralight and “flap-fly”—something that tires them quickly. “Sometimes they just drop out,” says Duff. “That’s when a chase plane will come down and pick that bird up.” A second pilot, also in a Cosmos ultralight, moves his wing right in front of the struggling bird, which will latch onto the wing’s vortex. In this way, the team will travel between 23 to 200 miles a day.

By 1941, the whooping crane population had dropped to 15; when Operation Migration led its first crane migration in 2004, the population had risen to 200; it’s now 500. For the species to survive, cranes must migrate on their own. In 2006, a crane trained by Operation Migration soloed from Florida to Wisconsin—the first to do so in more than 100 years.

Robert Harris Grob 102 Standard Astir III

A small road sign—Sailplane rides $5—sparked an eight-year obsession that culminated in a world record.

When Robert Harris took his first sailplane ride, in Hemet, California, in 1978, he had no idea he’d sign up for lessons and eventually buy a Grob 102.

“I don’t know how many years I had it,” says Harris, “when I thought I’ve got to do something more with this plane than just fly around the airport.”

Harris had heard of Paul Bickle’s 1961 altitude record—46,267 feet—and decided to try to break it. “I knew nothing about high-altitude flying,” says Harris. But he eventually partnered with someone who did: Jim Meyer, a U-2 pilot. He and Meyer flew together in the two-seat Twin for three years.

“We accumulated a lot of information,” says Harris, “and we were learning gradually what made mountain waves. We had 12 flights over 30,000 feet, and five flights over 35,000 feet. The highest we ever got was 39,800 feet.”